Special number services such as, by way of example and not by way of limitation, the Emergency Service E9-1-1 network in the United States, were implemented primarily in a voice network. The relatively recent introduction of text message (also referred to as text messaging) formats conveyed via voice networks has provided additional capabilities for the E9-1-1 network as well as other special number networks. For example, deaf persons may access the E9-1-1 network using a text messaging format without special equipment or connections to a special network. Similarly, when a calling station is unattended (e.g., a mobile station such as an ACN (Automatic Collision Notification) system), an emergency notification message may be automatically provided via a network in a text messaging format.
Text messaging communication may employ a format such as Short Message Service (SMS) or Unstructured Supplementary Service Data (USSD) and may be conveyed using control channels or other communication channels associated with a telecommunication network. By way of example and not by way of limitation, telecommunication networks may employ various types of signaling in various channels of communication to effect the desired routing, connection, packetizing and other functions associated with carrying out desired communications. By way of example and not by way of limitation, a switching protocol known as Signaling System-7 (SS-7) may be employed for supporting such network functions as call-establishment, billing, routing, and information exchange functions in a Public Switched Telephone Network (PSTN). SS-7 may identify functions to be performed by a signaling system PSTN and a protocol to enable performance of the identified functions. SS-7 may be used to support communications using a text messaging format.
Text messaging formats, such as by way of example and not by way of limitation, SMS format, may permit transmission of alphanumeric messages between a mobile subscriber and external systems such as electronic mail, paging, voice mail systems and special number systems (e.g., Emergency Service Systems). To date, there has not been a “marriage” of special number dialing and text message format messages. That is, until now one who desired to communicate with a special number system, such as an Emergency Service system, using a test messaging format had to dial a seven-or ten-digit number to reach a responsive entity. For example, one would have to dial a seven-or ten-digit number to reach a Public Safety Answering Position (PSAP; sometimes referred to as a Public Safety Answering Point) using a text messaging format in order to report an emergency situation requiring assistance. One could not dial a shortened calling number when employing a text messaging format to reach a PSAP, such as by way of example and not by way of limitation dialing “9-1-1”.
Further, special number calling systems have originated and developed based upon an assumption that the origination locus of a special number call is known prior to the initiation of the call. This presumption has traditionally been correct because the specific address and location at an address is associated with every telephone number that supports fully capable special number calling.
Known location information is preferably used to route E9-1-1 calls to an appropriate PSAP near the origin of the call. The same information may be used by the PSAP to support the emergency response to the call, such as dispatching fire, police or emergency medical personnel and equipment and for call back to the call originator if necessary. However, origin of a special number call is often not known when the call is placed using a mobile phone.
If location information relating to a mobile phone provides only coarse mobile network cell-level granularity to an E9-1-1 PSAP, police or emergency service personnel may go to a location indicated for a particular phone number and find that they have arrived at a large office building or at a widespread college campus with no means available for locating the caller with greater accuracy. Valuable time may be spent in finding the particular locus of the caller to render the required assistance. Such delays can be life threatening in the case of emergency service calls.
Location technologies have more recently been developed, such as GPS (Global Positioning Satellite) technology to assist in locating mobile phones. However, to date there has been no “marriage” of locating technology with special number calling using text messaging format. That is, no system or method has been available to user so far permitting conveyance of location information from a mobile caller to a called party when using a text messaging format.
Short Message System or other textual format messaging communications may be advantageous in situations where a caller cannot advantageously utilize voice calling, such as, by way of example and not by way of limitation, when employed by a hearing impaired user. It remains important for hearing impaired users as well as hearing users to be able to route a Short Message (SM) special number call to a proximate special number answering station. That is, by way of example and not by way of limitation, to be able to route an emergency call to a PSAP that is proximate to the location of the mobile unit employed by the caller. Such proximate routing permits a greater likelihood of timely provision of emergency services where they are needed. The problem is that presently deployed systems that are capable of providing accurate location information for a mobile communication unit utilize voice communication channels for conveying the geographic information. As a result, an unattended voice channel for a mobile call, such as when a hearing impaired user places a call, may not avail the called network access of accurate location information relating to the mobile calling station.
There is a need for a system and method for handling special number calls with an automatic location function that recognizes a shortened calling number using a text message format and that is capable of providing location information relating to the mobile calling unit used to place the call.